Steering device for marine drive units



March 2, 1965 s. KUHN STEERING DEVICE FOR MARINE DRIVE UNITS 3 Sheets-Sheet Filed Aug. 27. 1962 INVENTOR. Gee/M20 lfmw BY I ,fia 7% March 2, 1965 e. KUHN STEERING DEVICE FOR MARINE DRIVE uurrs Filed Aug. 27. 1962 3 Sheets-Sheet 2 INVENTOR. Gale/M20 (04w F1425. .5 iwpw March 2, 1965 G. KUHN STEERING nsvxcs FOR MARINE DRIVE nuns 5 Sheets-Sheet 3 Filed Aug. 27, 1962 y wk r m N 2 irranvers United States Patent 3,171,380 STEERING DEVICE FOR MARINE DRIVE UNITS Gerhard Kuhn, Circle Pines, Minn., assignor to McCulloch Corporation, Los Angeles, Calif., a corporation of Wisconsin Filed Aug. 27, 1962, Ser. No. 219,676 1 Claim. (Cl. 114-450) This invention relates generally to the steering of boats through the turning of outboard motors or outboard drive units and particularly concerns such steering from a remote point through the use of fluid pressure.

The primary object of the invention is to provide a new and improved means for turning an outboard motor, drive unit, rudder or the like mounted at or near the stern of a marine craft for purposes of steering the craft through operation of a forwardly and remotely mounted control such as a steering wheel, with said means operating through the use of fluid pressure in a completely enclosed system eliminating the use of seals where fluid leakage can occur.

With this and other objects in mind the invention broadly comprises a system having fluid chambers respectively adajacent the craft steering control and motor or unit to be turned to effect the steering, said chambers being interconnected by a fluid carrying conduit, each of said chambers having a flexible diaphragm forming one wall thereof so that the chambers and conduit jointly form a completely sealed unit and with the diaphragm in one chamber being mechanically connected to the control for actuation thereby and the diaphragm in the other chamber being mechanically connected to the motor or unit to effect turning thereof, and the conduit and chambers intermediate the diaphragms being filled with a fluid.

The above mentioned and still additional objects of the invention will be brought to light during the course of the following specification, reference being made to the accompanying drawings, in which-- FIG. 1 is a longitudinal vertical section through a boat with a conventional outboard motor mounted on the transom thereof and showing the motor connected to a steering control mounted at a forward point on the boat by the steering system of the present invention.

FIG. 2 is a vertical section taken through the front steering control unit housing mounted at the front of the boat with the control mechanism shown in side elevation.

FIG. 3 is a horizontal section through the rear steering control unit with the control mechanism shown in plan.

FIG. 4 is a longitudinal vertical section taken through the front control unit of a modified form of the invention.

FIG. 5 is a plan view, with the housing shown in horizontal section, of the rear unit used in combination with the control unit shown in FIG. 4.

Referring now more particularly to the drawings reference characters will be used to denote like parts and structural features in the different views. A marine craft of the runabout type used to illustrate the invention is designated generally at 10. The craft has a transom wall 11 extending transversely across the stem end. An outboard motor 12 is mounted on the transom 11 by means of a boat bracket 14. An operators seat 15 is positioned at a forward point in the craft behind the conventional windshield 16 and dashboard 17 with a bow compartment 18 located forwardly of the dashboard 17.

A steering wheel 19 is fixed on one end of the control shaft 20 which extends through the panel 17 being journaled for rotation in the bearing 21 mounted on the panel.

Turning now to FIG. 2, a housing 24 is mounted as by bracket 25 within the compartment 18 and has an opening 26 for receiving the forward portion of the rotatable control shaft 20. At the fore and aft ends of the housing and interior thereof there are formed front and rear fluid chambers, denoted respectively at 27 and 28. These chambers are isolated from the center area in the housing by means of flexible diaphragms 29 and 30 which have their edges peripherally clamped between sections of the housing.

Bearing members 31 mounted within the housing 24 slidably support a ram member 32, the ends of which are respectively secured to the central portions of the diaphragms 29 and 30. A gear rack 34 having its teeth aligned parallel with the axis of shaft 20 is integrally mounted on the ram 32 as by means of the support block 35. A worm gear 36 is nonrotatably secured upon the shaft 20 between the sleeve 37 and nut 38 with the spiral teeth thereof in constant mesh with the teeth on gear rack 34.

It will now be understood that as the shaft 26 is turned in one direction, by manual operation of the wheel 19, gear 36 being in mesh with the segment 34 will cause the ram to be moved longitudinally flexing the diaphragms and contracting one of the chambers 27, 28 and expanding the other. Reverse turning movement of the shaft 20 will have an opposite effect upon the respective chambers. In the construction shown, rotation of the Wheel 19 in a clockwise direction as viewed from the operators seat will cause contraction of the chamber 28 while counterclockwise turning will cause contraction of the forward chamber 27 Reverting now momentarily to FIG. 1, it should be explained that the motor 12 is mounted on the bracket 14 by means of a pivot bracket 48. This bracket is pivoted as at 41 to the boat bracket 14 for fore and aft tilt-ing movement about a transverse axis. Bracket 40 integrally carries a swivel tube 42 at its rear end which journals a steering pintle 44 (FIG. 3) on the motor. Accordingly, while the motor and bracket 40' are tiltable about the pivot axis 41, the motor alone is turned for steering the craft about the upright axis of tube 42 and pintle 44 journaled therein. In the present construction bracket 40 is provided with a forward extension 45, the purpose of which will shortly become apparent.

It is, of course, conventional practice to steer marine craft propelled by an outboard motor by merely turning the motor about its upright axis, thus shifting the direction of the propeller force against the boat transom. Thus, it will be readily understood that in the construction shown as the motor 12 is rotated clockwise, as viewed from above, about pintle 44, the force of propeller 46 will cause the craft 10 to turn to the left and reverse rotation will cause it to turn to the right.

Turning now to FIG. 3 the present invention will be further described in detail. A housing 47 is mounted on the forward extension 45 of the pivot bracket 40. FIG. 3 is a horizontal section through this housing and shows the mechanism connecting the housing with the motor steering pintle 44. The housing is elongated transversely of the boat and has left and right fluid chambers 48 and 49 formed in the ends thereof. These chambers are respectively isolated from the central portion of the housing by flexible diaphragms 50 and 51. The diaphragms are interconnected by a bar 52 having a rearwardly facing rack portion 54. Immediately forward of the rack 54 a gear member, designated generally at 55, is pivoted to the housing on pin 56. The member includesan annularportion 57 journalled on pin 56 and having a gear segment 58 with teeth projecting forwardly into intermeshing relation with the rack 54. An arm 59 extends rearwardly from portion 57 and carries a gear sector 60 at its rear end with a series of teeth 61 horizontally alignedalon-g an are on itsrearedge; The gear segments 61 and 58 are each formed on an'arc having the axis of pin 56 as a center. V

A plate 64 is fixed-to pintle-44 as by bolt 65-and key 66 and extends forwardly from the 'pint-lewith theforward portion thereofcarryingagear-segrnent 67 having an arcuate series'of rearwardly-projectingteeth 68formed on an arc of pintle 44 and disposed in intermeshing relation with the teeth 61' onthe member 55-. a A: collar 69 of'flexible material has one en'd fastened tothehousing 47 as by a retainer ring7.0 and its rear end secured around the arm portion 59 of-member 55 as by ring 71 to close the rear end of the housing'against-the entrance of moisture andcontamination.

It will be noted in FIG. Z'thatthehousing--24 is provided with fluidrports 74--and 7-5 respectively entering into the chambers 27' and28. In the same manner the housing 47 is provided with ports 76 and 77" respectively entering into the chambers-48 and 49 Fluid carrying flexible lines 78 and '79 (FIG. 1) shown diagrammatically in FIGS. 2 and3 having suitable connector nipples, at their ends provide closed-connections respectively between the ports '74 and- 77*and the ports and 76. The chambers 27; 28;- 48-and 49 and their interconnecting lines 78 and .79 arefilledwith a'suitable fluid medium such. as a commonhydraulic liquid. Chambers 28 and 48'- and their connecting line 79- thus combine to form a first sealed liquid carying enclosure and chambers 27 and 49 and their connecting line 78- combine to form the second. n

It will now be understood that as the wheel 19 is turned to the right or clockwise as-viewed fromthe rear to contract the chamber 28-, thefluid pressure in the line 79 and chamber 48 will cause the latter to expand. As the diaphragm 50 moves outwardly the member 52'meshing with member 55 through teeth 54 and 58 willcause the member 55 to swing about pin 56 toward the position shown in broken lines. This, of course; turns plate 67 and the motor connected thereto about-the axis ofpintle 44 to the broken line position-which turns the craft toward the right as desired. I

Opposite movement of the wheel 19' will, of course, through the same mechanism and utilizing the fluid in line 78, turn the motor in an opposite direction-to steer the boat toward the left; V n

A different embodiment of the invention'is shown in FIGS 4 and 5 utilizing single fluid chambers in the front and'rear control'units'with a single connecting fluid line.

Here the steering wheel mounting and shaft 20 and the motor steering pintle 44 and the member 64; 67 coning the forward portion of the shaft-20i- Afluid cham ber 82 is disposed in the forward portion of the-housing being isolated from the remainder of the housing interior by an annularly corrugated metal diaphragm 84. An

insert assembly mountedwithin the housing has an upper bearing portion 85-for journalingshaft 20'and a lower bearing portion 86, 87'supporting a ram member 88 for longitudinal sliding movement, A longitudinally extending slot-89'is provided on the underside. of member-88 for receiving a guide pin 90 anchored in thewall of the housing. The forward end-of member 88 is secured to the center of the diaphragm .84..as by nut and washer V assembly 91. A" worm gear 92 is secured to the front end of the shaft 20 with .the spiral teeth thereof in meshing engagementwitha series of aligned teeth 9 4formed in the central upper portion of theram member 88;:

It will be understood that as shaft 20 is turned counterclockwise as viewed from the rear or the left in FIG. 4, the gear 92-will cause the ram element 88 to move forward contracting the chamber 82 and that reverse turning movement of the shaft 20 will conversely move the diaphragm to expand the chamber 82.

" A pair of transversely aligned bearings 98 support an elongated-bar 99 fortransverse slidinggniovement with the; forward side of, the bar having. a rack of gear teeth 1&9- formed therein- A pivot pm 101 is anchored in the housing wall and journals, an annular hub 102 having a small rearwardly directed gear segment 104 on the upper. portion thereof, which is. in meshing engagement with. the rack. 1001. From the lower portion of hub 102. an elongatedgear sector. 105 extends rearwardly having a toothed segment. 106 formed along its rear edge. 7 A gear. member, designated generally by numeral 107 and havinga construction similar to member 59v shown in FIG. 3., is mounted to. therear of the bar 9 9 with an annular portion 109 thereof journaled on. a pivot pin 108. Portion 109 has a forwardly projecting gear segment lltldisposed in meshwith segment 106, The member 107 has a swing, arm 111'extendingrearwardly. from the annularportion 109 and carrying a gear sector 112 at its rear end with 'an arcuate series of teeth; meshing with the teeth 68" on the. plate. 67. A closure collar 115 of. flexible material has its ends. secured respectively to the. arm 111 and housing 96 by sanp rings 1'16 and 117.

The housingfitlis provided with a port 118. leading intothe chamber 82 and housing 96has a port 119 leade ing into chamber. 97. These-ports are interconnected by a fluid line 120. shown. diagrammatically in FIGS. 4 and 5, so that the chambers 82 and 97' along with the. line 120kjointly form a completely sealed fluid enclosure which'is filled with a suitable, preferably liquid, fluid medium. n r

The metaldiaphragm shown in this form oftheinven- 'tion is double acting and does not present the backlash problems 'of themoreflexible diaphragm shown in the first embodiment. It isthuspossible to provide a very satisfactory system with only a single fluid line.

In operation, as control shaft 20isrotated to advance ram 88, the chamber-82 is contracted with, corresponding expansion of the chamber 97 as fluid moves, rearwardly through the line.120.. With. the expansion ofthe. chamber 97 thediaphragm 97% will bulge. outwardlyfrom the chambermovingthe bar 99 to the left'(upwardly as viewed in FIG. 5 withteeth 100' meshingw-ith teeth',104 and swinging the member 105 in the same directionaboutthe pin 101. This movement will in turn, throughthe. intermeshing of teeth 106 and 110, swing member 107'in the oppositedirection about pin 108 and through theinte'r meshing of teeth-6 8: with fteeth 114 turn plate .67 and the motor to which it is connectedina clockwise direction as viewed irrFlG. 5 -ab out.the. axis of pintle 44 to turn the course of .the boat-toward the left. I

As the shaft 20 is turned in theopposite direction to expandthe chamber 82through the pullingof diaphragm 84.0utwardly, the suction created within the chambers 82 and 97 and line 120; will causeathe diaphragm 97 to bedrawn intochamber 97 and through oppositev move- ;ment of the members. 919; 105, 111 and 64 cause the. motor to rotate in'an opposite direction so as to turn the course of the boat toward theright. v p

The corrugated.metaldiaphragms. 84 and 97 being double acting, havev sufficient rigidity. to prohibit back-' lash. thus enabling the, concept to be. carried out in this form ofthe; inven-tion'through use-of a The invention as set forth in the embodiments described thus provides a hydraulic steering system which is completely enclosed eliminating any possibility of leakage. The system does not utilize any rods sliding through seals Which would allow such leakage and cause considerable Wear or fatigue on the parts involved. With the fluid sealed in, the system requires a minimum of maintenance.

It will further be understood that the system can readily be incorporated on any marine craft having a turn-table outboard motor or power unit. T he fluid tubes or lines, at least throughout the greatest portion of their extension, can be of a rigid nature and can in fact be built into the craft.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come Within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, What I claim to be new and desire to protect by Letters Patent is:

A steering system for controlling an outboard motor mounted at the aft end of a boat from a rotary steering shaft mounted forwardly on the boat, a pair of independent fluid chambers mounted adjacent the shaft and spaced longitudinally thereof, said chambers having facing flexible diaphragrns, an elongated diaphragm actuating element extending between the diaphragms and having its ends respectively connected one to each diaphragm, said element having a gear rack thereon with a series of teeth facing the shaft, a Worm gear on the shaft in meshing engagement with the rack for moving the actuating element longitudinally of the shaft to move said diaphragms to enlarge the size of one chamber and reduce the size of the other as the shaft is rotated, a steering control member on the motor, and fluid means connecting the control member tosaid chambers for movement of the member in one direction as one chamber is reduced in size and in the opposite direction as the other chamber is reduced in size.

References Cited in the file of this patent UNITED STATES PATENTS 2,592,221 Whitted Apr. 8, 1952 2,855,755 Auger Oct. 14, 1958 2,891,498 Schroeder June 23, 1959 3,084,657 Kiekhaefer Apr. 9, 1963 

